Respiratory profile and gill histopathology of Carassius auratus exposed to different salinity concentrations / Perfil respiratório e histopatologia das brânquias de Carassius auratus expostas a diferentes concentrações de salinidades

The aim of this study was to evaluate the chronic salinity tolerance of Carassius auratus and the effects on blood parameters, gill morphology, and survival. In the first test, nine different concentrations (0.0, 0.5, 1.0, 2.5, 5.0, 10, 15, 20, and 25 g L-¹) of NaCl were used with nine repetitions for 96 h. The survival of fish subjected to 15 g L-¹ NaCl was 4 h, and 5 min at a concentration of 25 g L-¹. The mortality of fish with 15g L-¹ NaCl was 100%. Morphological analyses of the gills showed hyperplasia of the coated cells in the interlamellar space and hypersecretion of mucus in fish exposed to 10 g L-¹ of NaCl. At concentrations of 20 and 25 g L-¹, necrosis of the support collagen caused the cells to detach from the lamellar structure mucosa. In the chronic test, two concentrations were used, with four replications containing nine fish in each aquarium for a period of 21 days. Blood samples and gills from the fish were collected, and it was observed that the fish showed a decrease in the concentration of bicarbonate (NaHCO3) in the blood, indicating hypernatremia. Acute exposure of C. auratus to sodium chloride (NaCl) should be at a maximum of 10 g L-¹ of NaCl, after which level there would be a loss in animal performance and/or mortality. Chronic exposure to 5 g L-¹ of NaCl promotes acidemia, ionic imbalance, and pathological changes in the gills; therefore, it is not recommended.

O objetivo deste estudo foi avaliar a tolerância crônica de Carassius auratus à salinidade e os efeitos sobre os parâmetros sanguíneos, morfologia branquial e sobrevivência. No primeiro teste, foram utilizadas nove concentrações de NaCl (0.0, 0.5, 1.0, 2.5, 5.0, 10, 15, 20, e 25 g L-¹) e nove repetições por 96 h. A sobrevivência dos peixes submetidos a até 15 g L-¹ de NaCl foi de 04h00, sendo 00h05 na concentração de 25 g L-¹ de NaCl. A mortalidade dos peixes com 15 g foi de 100%. As análises morfológicas das brânquias mostraram hiperplasia das células revestidas no espaço interlamelar e hipersecreção de muco em peixes expostos a uma concentração de 10 g L-¹ de NaCl. Nas concentrações de 20 e 25 g L-¹, observou-se que a colágeno de suporte perdeu a estrutura das células da mucosa, alterando as lamelas secundárias. Em um segundo experimento, um delineamento inteiramente casualizado foi utilizado com dois tratamentos (0 e 5g L-¹ de NaCl) e quatro repetições com nove peixes por 30 L em 21 dias. Amostras de sangue e brânquias dos peixes foram coletadas e observou-se que os peixes apresentaram diminuição nas concentrações de bicarbonato (NaHCO3) no sangue, indicando hipernatremia. Conclui-se que a exposição aguda de C. auratus ao cloreto de sódio (NaCl) deve ser de no máximo 10 g L-¹, levando à perda de desempenho e/ou mortalidade dos animais. A exposição crônica a 5 g L-¹ de NaCl promove acidemia, desequilíbrio iônico e alterações patológicas nas brânquias, por isso não é recomendado.

Respiratory profile and gill histopathology of Carassius auratus exposed to different salinity concentrations / Perfil respiratório e histopatologia das brânquias de Carassius auratus expostas a diferentes concentrações de salinidades

The aim of this study was to evaluate the chronic salinity tolerance of Carassius auratus and the effects on blood parameters, gill morphology, and survival. In the first test, nine different concentrations (0.0, 0.5, 1.0, 2.5, 5.0, 10, 15, 20, and 25 g L-¹) of NaCl were used with nine repetitions for 96 h. The survival of fish subjected to 15 g L-¹ NaCl was 4 h, and 5 min at a concentration of 25 g L-¹. The mortality of fish with 15g L-¹ NaCl was 100%. Morphological analyses of the gills showed hyperplasia of the coated cells in the interlamellar space and hypersecretion of mucus in fish exposed to 10 g L-¹ of NaCl. At concentrations of 20 and 25 g L-¹, necrosis of the support collagen caused the cells to detach from the lamellar structure mucosa. In the chronic test, two concentrations were used, with four replications containing nine fish in each aquarium for a period of 21 days. Blood samples and gills from the fish were collected, and it was observed that the fish showed a decrease in the concentration of bicarbonate (NaHCO3) in the blood, indicating hypernatremia. Acute exposure of C. auratus to sodium chloride (NaCl) should be at a maximum of 10 g L-¹ of NaCl, after which level there would be a loss in animal performance and/or mortality. Chronic exposure to 5 g L-¹ of NaCl promotes acidemia, ionic imbalance, and pathological changes in the gills; therefore, it is not recommended.(AU)

O objetivo deste estudo foi avaliar a tolerância crônica de Carassius auratus à salinidade e os efeitos sobre os parâmetros sanguíneos, morfologia branquial e sobrevivência. No primeiro teste, foram utilizadas nove concentrações de NaCl (0.0, 0.5, 1.0, 2.5, 5.0, 10, 15, 20, e 25 g L-¹) e nove repetições por 96 h. A sobrevivência dos peixes submetidos a até 15 g L-¹ de NaCl foi de 04h00, sendo 00h05 na concentração de 25 g L-¹ de NaCl. A mortalidade dos peixes com 15 g foi de 100%. As análises morfológicas das brânquias mostraram hiperplasia das células revestidas no espaço interlamelar e hipersecreção de muco em peixes expostos a uma concentração de 10 g L-¹ de NaCl. Nas concentrações de 20 e 25 g L-¹, observou-se que a colágeno de suporte perdeu a estrutura das células da mucosa, alterando as lamelas secundárias. Em um segundo experimento, um delineamento inteiramente casualizado foi utilizado com dois tratamentos (0 e 5g L-¹ de NaCl) e quatro repetições com nove peixes por 30 L em 21 dias. Amostras de sangue e brânquias dos peixes foram coletadas e observou-se que os peixes apresentaram diminuição nas concentrações de bicarbonato (NaHCO3) no sangue, indicando hipernatremia. Conclui-se que a exposição aguda de C. auratus ao cloreto de sódio (NaCl) deve ser de no máximo 10 g L-¹, levando à perda de desempenho e/ou mortalidade dos animais. A exposição crônica a 5 g L-¹ de NaCl promove acidemia, desequilíbrio iônico e alterações patológicas nas brânquias, por isso não é recomendado.(AU)

Photosensitization in cattle caused by spontaneous and experimentally ingestion of Stryphnodendron fissuratum

Background: Stryphnodendron fissuratum is a tree from the Brazilian Cerrado. Its fruit is toxic to cattle and can cause clinical digestive signs, hepatogenous photosensitization, and abortion. Cases of poisoning in cattle, goats and guinea pigs have been experimentally reproduced; however, photosensitization could not be reproduced. The aim of this work was to describe an outbreak of natural poisoning and experimental reproduction in cattle, both with hepatogenous photosensitization.Materials, Methods & Results: Its described and natural outbreak and an experimental poisoning. In the outbreak, three bovines in the acute phase and three in the chronic phase were examined. Blood samples were collected from all of these animals in order to measure serum levels of aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), urea, and creatinine. The first three animals underwent necropsy and histopathological evaluation. The experiment was conducted with two nine-month-old calves that received an oral paste made with crushed S. fissuratum fruits mixed with water. These fruits were collected at a farm at which cattle poisoning cases had occurred. Blood samples were collected in order to measure serum levels of AST, GGT, urea, and creatinine, before plant administration and then daily during the experimental period. Skin biopsies were taken before plant administration and new one after the first signs of skin lesions. The natural outbreak affected 52 of 160 bovine (31 calves and 21 cows) in the lot. Two calves and 14 cows died. Clinical signs consisted of depression, ataxia, incoordination, behavioral changes, decubitus, and death. One animal that died and 36 others that recovered had photodermatitis. Necropsy findings in the animals consisted of bad corporal condition, pale kidneys, evidence of liver lobular pattern, dry rumen contents, and full bladder.[...]

Photosensitization in cattle caused by spontaneous and experimentally ingestion of Stryphnodendron fissuratum

Background: Stryphnodendron fissuratum is a tree from the Brazilian Cerrado. Its fruit is toxic to cattle and can cause clinical digestive signs, hepatogenous photosensitization, and abortion. Cases of poisoning in cattle, goats and guinea pigs have been experimentally reproduced; however, photosensitization could not be reproduced. The aim of this work was to describe an outbreak of natural poisoning and experimental reproduction in cattle, both with hepatogenous photosensitization.Materials, Methods & Results: Its described and natural outbreak and an experimental poisoning. In the outbreak, three bovines in the acute phase and three in the chronic phase were examined. Blood samples were collected from all of these animals in order to measure serum levels of aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), urea, and creatinine. The first three animals underwent necropsy and histopathological evaluation. The experiment was conducted with two nine-month-old calves that received an oral paste made with crushed S. fissuratum fruits mixed with water. These fruits were collected at a farm at which cattle poisoning cases had occurred. Blood samples were collected in order to measure serum levels of AST, GGT, urea, and creatinine, before plant administration and then daily during the experimental period. Skin biopsies were taken before plant administration and new one after the first signs of skin lesions. The natural outbreak affected 52 of 160 bovine (31 calves and 21 cows) in the lot. Two calves and 14 cows died. Clinical signs consisted of depression, ataxia, incoordination, behavioral changes, decubitus, and death. One animal that died and 36 others that recovered had photodermatitis. Necropsy findings in the animals consisted of bad corporal condition, pale kidneys, evidence of liver lobular pattern, dry rumen contents, and full bladder.[...](AU)

Experimental poisoning by Enterolobium contortisiliquum in sheep / Intoxicação experimental por Enterolobium contortisiliquum em ovinos

Ingestion of Enterolobium contortisiliquum pods causes digestive disturbances, secondary hepatogenous photosensitization and abortions in ruminants. Pods were administered to sheep via a ruminal cannula to characterize acute poisoning. In Experiment 1, a single dose of 12g/kg of body weight (BW) was administered to three sheep in one experiment. One sheep died, and the other two recovered after presenting clinical signs. In Experiment 2, 10g/kg BW were administered daily to 15 sheep until the onset of clinical signs or for three consecutive days. Fourteen sheep showed mild to severe signs after the ingestion of 1-3 doses. Two sheep died, and the others recovered. Clinical signs in both experiments were diarrhea, anorexia, rumen atony, apathy, dehydration and tachypnea. The main macroscopic findings were an orange, frothy ruminal content witch contained pods fragments. The intestinal content was liquid. Detachment of the mucosa from the submucosa and ballooning degeneration of mucosal cells were observed histologically in the forestomachs. Evaluation of ruminal contents revealed acute lactic ruminal acidosis (ALRA). Bromatological analysis of E. contortisiliquum pods revealed 537.8g/kg DM (dry matter) of non-fibrous carbohydrates, which is sufficient to cause ALRA. Only one sheep in Experiment 2 had liver failure, characterized by jaundice, elevated serum activity of liver enzymes and histological lesions in liver biopsies. It is concluded that the administration of E. contortisiliquum pods in forage-fed sheep at doses of 10g/kg BW or higher may cause ALRA. The induction of liver failure in one sheep suggests that liver damage may occur in those sheep that do not develop acidosis.(AU)

A ingestão das favas de Enterolobium contortisiliquum causa distúrbios digestivos, fotossensibilização hepatógena e abortos em ruminantes. Para caracterizar a intoxicação aguda, favas de E. contortisiliquum foram administradas a ovinos por meio de cânula ruminal. No Experimento 1, uma dose única de 12g/kg de peso corporal (pc) foi administrada a três ovinos. Um dos ovinos morreu e os outros dois se recuperaram após mostrar sinais clínicos. No experimento 2, 10g/kg/pc foram administradas diariamente a 15 ovinos, por três dias consecutivos ou até o parecimento dos sinais clínicos. Catorze ovinos mostraram sinais clínicos leves a acentuados após ingestão de 1-3 doses. Dois ovinos morreram e os outros se recuperaram. Observou-se nos ovinos dos experimentos 1 e 2, diarreia, anorexia, atonia ruminal, apatia, desidratação e taquipneia. Os principais achados macroscópicos incluíram conteúdo ruminal espumoso e alaranjado em meio ao qual se observavam fragmentos das favas de E. contortisiliquum, e conteúdo intestinal líquido. Histologicamente, havia degeneração balonosa e desprendimento do epitélio de revestimento dos pré-estomagos. A avaliação do conteúdo ruminal revelou acidose ruminal láctica aguda (ARLA). Análise bromatológica das favas de E. contortisiliquum revelou 537.8g/kg de matéria seca de carboidratos não fibrosos, quantidade suficiente para causar ARLA. Um ovino do Experimento 2 teve insuficiência hepática aguda, caracterizada por icterícia, elevação da atividade sérica das enzimas hepáticas e alterações histológicas observadas em biópsia hepática. Concluiu-se que a administração de favas de E. contortisiliquum na alimentação de ovinos, nas doses de 10g/kg pc ou maiores, pode causar ARLA. A ocorrência de insuficiência hepática num dos ovinos deste experimento sugere que a lesão hepática pode se desenvolver em ovinos que não apresentam ARLA.(AU)

Experimental poisoning by Enterolobium contortisiliquum in sheep / Intoxicação experimental por Enterolobium contortisiliquum em ovinos

Ingestion of Enterolobium contortisiliquum pods causes digestive disturbances, secondary hepatogenous photosensitization and abortions in ruminants. Pods were administered to sheep via a ruminal cannula to characterize acute poisoning. In Experiment 1, a single dose of 12g/kg of body weight (BW) was administered to three sheep in one experiment. One sheep died, and the other two recovered after presenting clinical signs. In Experiment 2, 10g/kg BW were administered daily to 15 sheep until the onset of clinical signs or for three consecutive days. Fourteen sheep showed mild to severe signs after the ingestion of 1-3 doses. Two sheep died, and the others recovered. Clinical signs in both experiments were diarrhea, anorexia, rumen atony, apathy, dehydration and tachypnea. The main macroscopic findings were an orange, frothy ruminal content witch contained pods fragments. The intestinal content was liquid. Detachment of the mucosa from the submucosa and ballooning degeneration of mucosal cells were observed histologically in the forestomachs. Evaluation of ruminal contents revealed acute lactic ruminal acidosis (ALRA). Bromatological analysis of E. contortisiliquum pods revealed 537.8g/kg DM (dry matter) of non-fibrous carbohydrates, which is sufficient to cause ALRA. Only one sheep in Experiment 2 had liver failure, characterized by jaundice, elevated serum activity of liver enzymes and histological lesions in liver biopsies. It is concluded that the administration of E. contortisiliquum pods in forage-fed sheep at doses of 10g/kg BW or higher may cause ALRA. The induction of liver failure in one sheep suggests that liver damage may occur in those sheep that do not develop acidosis.(AU)

A ingestão das favas de Enterolobium contortisiliquum causa distúrbios digestivos, fotossensibilização hepatógena e abortos em ruminantes. Para caracterizar a intoxicação aguda, favas de E. contortisiliquum foram administradas a ovinos por meio de cânula ruminal. No Experimento 1, uma dose única de 12g/kg de peso corporal (pc) foi administrada a três ovinos. Um dos ovinos morreu e os outros dois se recuperaram após mostrar sinais clínicos. No experimento 2, 10g/kg/pc foram administradas diariamente a 15 ovinos, por três dias consecutivos ou até o parecimento dos sinais clínicos. Catorze ovinos mostraram sinais clínicos leves a acentuados após ingestão de 1-3 doses. Dois ovinos morreram e os outros se recuperaram. Observou-se nos ovinos dos experimentos 1 e 2, diarreia, anorexia, atonia ruminal, apatia, desidratação e taquipneia. Os principais achados macroscópicos incluíram conteúdo ruminal espumoso e alaranjado em meio ao qual se observavam fragmentos das favas de E. contortisiliquum, e conteúdo intestinal líquido. Histologicamente, havia degeneração balonosa e desprendimento do epitélio de revestimento dos pré-estomagos. A avaliação do conteúdo ruminal revelou acidose ruminal láctica aguda (ARLA). Análise bromatológica das favas de E. contortisiliquum revelou 537.8g/kg de matéria seca de carboidratos não fibrosos, quantidade suficiente para causar ARLA. Um ovino do Experimento 2 teve insuficiência hepática aguda, caracterizada por icterícia, elevação da atividade sérica das enzimas hepáticas e alterações histológicas observadas em biópsia hepática. Concluiu-se que a administração de favas de E. contortisiliquum na alimentação de ovinos, nas doses de 10g/kg pc ou maiores, pode causar ARLA. A ocorrência de insuficiência hepática num dos ovinos deste experimento sugere que a lesão hepática pode se desenvolver em ovinos que não apresentam ARLA.(AU)

Experimental poisoning by Enterolobium contortisiliquum in sheep

ABSTRACT: Ingestion of Enterolobium contortisiliquum pods causes digestive disturbances, secondary hepatogenous photosensitization and abortions in ruminants. Pods were administered to sheep via a ruminal cannula to characterize acute poisoning. In Experiment 1, a single dose of 12g/kg of body weight (BW) was administered to three sheep in one experiment. One sheep died, and the other two recovered after presenting clinical signs. In Experiment 2, 10g/kg BW were administered daily to 15 sheep until the onset of clinical signs or for three consecutive days. Fourteen sheep showed mild to severe signs after the ingestion of 1-3 doses. Two sheep died, and the others recovered. Clinical signs in both experiments were diarrhea, anorexia, rumen atony, apathy, dehydration and tachypnea. The main macroscopic findings were an orange, frothy ruminal content witch contained pods fragments. The intestinal content was liquid. Detachment of the mucosa from the submucosa and ballooning degeneration of mucosal cells were observed histologically in the forestomachs. Evaluation of ruminal contents revealed acute lactic ruminal acidosis (ALRA). Bromatological analysis of E. contortisiliquum pods revealed 537.8g/kg DM (dry matter) of non-fibrous carbohydrates, which is sufficient to cause ALRA. Only one sheep in Experiment 2 had liver failure, characterized by jaundice, elevated serum activity of liver enzymes and histological lesions in liver biopsies. It is concluded that the administration of E. contortisiliquum pods in forage-fed sheep at doses of 10g/kg BW or higher may cause ALRA. The induction of liver failure in one sheep suggests that liver damage may occur in those sheep that do not develop acidosis.

RESUMO: A ingestão das favas de Enterolobium contortisiliquum causa distúrbios digestivos, fotossensibilização hepatógena e abortos em ruminantes. Para caracterizar a intoxicação aguda, favas de E. contortisiliquum foram administradas a ovinos por meio de cânula ruminal. No Experimento 1, uma dose única de 12g/kg de peso corporal (pc) foi administrada a três ovinos. Um dos ovinos morreu e os outros dois se recuperaram após mostrar sinais clínicos. No experimento 2, 10g/kg/pc foram administradas diariamente a 15 ovinos, por três dias consecutivos ou até o parecimento dos sinais clínicos. Catorze ovinos mostraram sinais clínicos leves a acentuados após ingestão de 1-3 doses. Dois ovinos morreram e os outros se recuperaram. Observou-se nos ovinos dos experimentos 1 e 2, diarreia, anorexia, atonia ruminal, apatia, desidratação e taquipneia. Os principais achados macroscópicos incluíram conteúdo ruminal espumoso e alaranjado em meio ao qual se observavam fragmentos das favas de E. contortisiliquum, e conteúdo intestinal líquido. Histologicamente, havia degeneração balonosa e desprendimento do epitélio de revestimento dos pré-estomagos. A avaliação do conteúdo ruminal revelou acidose ruminal láctica aguda (ARLA). Análise bromatológica das favas de E. contortisiliquum revelou 537.8g/kg de matéria seca de carboidratos não fibrosos, quantidade suficiente para causar ARLA. Um ovino do Experimento 2 teve insuficiência hepática aguda, caracterizada por icterícia, elevação da atividade sérica das enzimas hepáticas e alterações histológicas observadas em biópsia hepática. Concluiu-se que a administração de favas de E. contortisiliquum na alimentação de ovinos, nas doses de 10g/kg pc ou maiores, pode causar ARLA. A ocorrência de insuficiência hepática num dos ovinos deste experimento sugere que a lesão hepática pode se desenvolver em ovinos que não apresentam ARLA.

Dermatophilosis in Nelore calves in Mato Grosso do Sul / Dermatofilose em bezerros da raça Nelore no Mato Grosso do Sul

The objective of this study was to describe two outbreaks of dermatophilosis in Nelore calves in the State of Mato Grosso do Sul with epidemiological characteristics peculiar to the Midwest. Morbidity and mortality rates were 50% and 0.0025% in the outbreak 1, and 12.5% and 10% in the outbreak 2, respectively. Only Nelore calves aging between 5 and 60 days were affected. Most cases occurred on pastures of Brachiaria brizantha during the rainy season. In both outbreaks, the signs started with skin thickening followed by weeping and crusting around the eyes and muzzle. In more severe cases, lesions disseminated throughout the face and the body, evolving to generalized marked thickening of the skin and wrinkling. Histology of skin lesions showed suppurative dermatitis and hyperkeratosis. The diagnosis was confirmed by viewing basophilic filamentous structures morphologically consistent with Dermatophilus congolensis in Gram stained smears. The treatment with streptomycin, oxytetracycline or penicillin associated with streptomycin used in calves demonstrated to be effective. The disease has been misdiagnosed, by the farmers, with hepatic photosensitization caused by Brachiaria spp. ingestion. This article discusses these results with the aim to help in the correct diagnosis of dermatophilosis, which is important to achieve the adequate treatment and effective control measures to minimize the losses caused by this disease.(AU)

O objetivo deste trabalho foi descrever dois surtos de dermatofilose em bezerros da raça Nelore no Estado de Mato Grosso do Sul com características epidemiológicas peculiares à região Centro-Oeste. As taxas de morbidade e letalidade foram de 50% e 0,0025% no surto 1 e, 12,5% e 10% no surto 2, respectivamente. Apenas bezerros da raça Nelore com idade entre 5 e 60 dias foram afetados. A maioria dos casos ocorreu em pastagens de Brachiaria brizantha durante o período chuvoso do ano. Nos dois surtos, os sinais se iniciavam com espessamento da pele, seguido por lacrimejamento e formação de crostas ao redor dos olhos e focinho. Nos casos mais graves, as lesões disseminavam-se pela face e por todo o corpo, evoluindo para acentuado espessamento generalizado da pele, com formação de dobras. As lesões de pele caracterizaram-se, histopatologicamente, por dermatite supurativa e hiperqueratose. O diagnóstico foi confirmado pela visualização de estruturas basofílicas filamentosas morfologicamente compatíveis com Dermatophilus congolensis em esfregaços corados por Gram. Os tratamentos com estreptomicina, oxitetraciclina ou penicilina associada à estreptomicina utilizados nos bezerros demonstraram ser eficientes. A doença foi confundida pelos produtores com fotossensibilização hepatógena causada por ingestão de Brachiaria spp. Este artigo discute estes resultados com vistas a auxiliar o diagnóstico correto da dermatofilose que é importante para a realização do tratamento adequado e de medidas de controle eficazes, minimizando as perdas causadas por esta doença.(AU)

Nonsuppurative myocarditis associated with bovine viral diarrhea virus infection in calves in the State of Mato Grosso do Sul, Brazil

Background: Bovine viral diarrhea virus (BVDV) refers to a heterogeneous group of viruses belonging to the family Flaviviridae and genus Pestivirus. This family of viruses is one of the main pathogens of cattle and causes significant economic losses to the cattle industry worldwide. BVDV is an enveloped virus with a diameter of 45 nm and single-stranded RNA genome of 12.5 kb. BVDV infection has been associated with a number of clinical manifestations ranging from unapparent infection and mild signs to acute illness and death. In general, calves are more susceptible to BVDV infection, but adult cattle can develop the clinical disease if they are infected with highly virulent virus strains. This study describes clinical, anatomopathological and epidemiological findings of a BVDV outbreak in calves in the state of Mato Grosso do Sul, Brazil. Materials, Methods & Results: The outbreak occurred in the town of Agua Clara in the state of Mato Grosso do Sul. Epidemiological and clinical data were collected by the farm manager during a visit to the property. The outbreak involved two Nelore heifer calves that died between 30 and 40 days of age. One calf was taken to the Laboratory of Pathological Anatomy (LAP) of the Faculty of Veterinary and Animal Husbandry, Federal University of Mato Grosso do Sul (FAMEZ/UFMS). The calf was necropsied, and white streaks were seen on the heart, indicating congestive failure with swelling of body cavities and congestive hepatopathy (nutmeg liver). Fragments of different organs and tissues were collected during necropsy, fixed in 10% formalin for 48 h, embedded in paraffin, cut in 5 µm sections and stained with hematoxylin-eosin (HE) or analyzed by immunohistochemistry (IHC) in the Veterinary Pathology sector of the Federal University of Rio Grande do Sul (UFRGS). Histologically, the heart lesion was characterized by fibrous coagulative necrosis associated with marked infi ltrate (predominantly lymphocytic) and some macrophages. The diagnosis was confirmed by immunohistochemical agent identification in Peyer's patches within the intestine. Discussion: The diagnosis of congestive heart failure due to myocarditis caused by BVDV infection was confirmed by the IHC technique. While in other countries, myocarditis caused by natural infection in cattle and experimental infection in goats and sheep due to BVDV has been described, there have been no reports of this clinical and pathological manifestation of the disease in Brazil. The heart lesions observed in the outbreak should be differentiated from similar injuries caused by certain plants and from Neospora caninum infection. In the present study, while the virus was identified by immunohistochemistry only in Peyer's patches, BVDV was considered to be the cause of the cardiac lesions by a process of elimination and because there is no correlation between the amount of viral antigen and the location of histological lesions. Other studies have used the IHC technique to detect BVDV antigen in other tissues of cattle and observed that the antigen is not uniformly distributed among the organs, suggesting that no specific organ of aborted fetuses can be chosen for BVDV diagnosis. Immunohistochemistry was shown to be an efficient method for detecting the antigen in the Peyer's patches of infected calves. This is the first report of nonsuppurative myocarditis associated with BVDV causing perinatal cattle death with agent identification in Mato Grosso do Sul. However, these data are insufficient to determine the importance of BVDV infection in terms of reproductive losses in this state because the methodological approaches used were different from those adopted in earlier studies.

Dermatophilosis in Nelore calves in Mato Grosso do Sul / Dermatofilose em bezerros da raça Nelore no Mato Grosso do Sul

The objective of this study was to describe two outbreaks of dermatophilosis in Nelore calves in the State of Mato Grosso do Sul with epidemiological characteristics peculiar to the Midwest. Morbidity and mortality rates were 50% and 0.0025% in the outbreak 1, and 12.5% and 10% in the outbreak 2, respectively. Only Nelore calves aging between 5 and 60 days were affected. Most cases occurred on pastures of Brachiaria brizantha during the rainy season. In both outbreaks, the signs started with skin thickening followed by weeping and crusting around the eyes and muzzle. In more severe cases, lesions disseminated throughout the face and the body, evolving to generalized marked thickening of the skin and wrinkling. Histology of skin lesions showed suppurative dermatitis and hyperkeratosis. The diagnosis was confirmed by viewing basophilic filamentous structures morphologically consistent with Dermatophilus congolensis in Gram stained smears. The treatment with streptomycin, oxytetracycline or penicillin associated with streptomycin used in calves demonstrated to be effective. The disease has been misdiagnosed, by the farmers, with hepatic photosensitization caused by Brachiaria spp. ingestion. This article discusses these results with the aim to help in the correct diagnosis of dermatophilosis, which is important to achieve the adequate treatment and effective control measures to minimize the losses caused by this disease.

O objetivo deste trabalho foi descrever dois surtos de dermatofilose em bezerros da raça Nelore no Estado de Mato Grosso do Sul com características epidemiológicas peculiares à região Centro-Oeste. As taxas de morbidade e letalidade foram de 50% e 0,0025% no surto 1 e, 12,5% e 10% no surto 2, respectivamente. Apenas bezerros da raça Nelore com idade entre 5 e 60 dias foram afetados. A maioria dos casos ocorreu em pastagens de Brachiaria brizantha durante o período chuvoso do ano. Nos dois surtos, os sinais se iniciavam com espessamento da pele, seguido por lacrimejamento e formação de crostas ao redor dos olhos e focinho. Nos casos mais graves, as lesões disseminavam-se pela face e por todo o corpo, evoluindo para acentuado espessamento generalizado da pele, com formação de dobras. As lesões de pele caracterizaram-se, histopatologicamente, por dermatite supurativa e hiperqueratose. O diagnóstico foi confirmado pela visualização de estruturas basofílicas filamentosas morfologicamente compatíveis com Dermatophilus congolensis em esfregaços corados por Gram. Os tratamentos com estreptomicina, oxitetraciclina ou penicilina associada à estreptomicina utilizados nos bezerros demonstraram ser eficientes. A doença foi confundida pelos produtores com fotossensibilização hepatógena causada por ingestão de Brachiaria spp. Este artigo discute estes resultados com vistas a auxiliar o diagnóstico correto da dermatofilose que é importante para a realização do tratamento adequado e de medidas de controle eficazes, minimizando as perdas causadas por esta doença.